This invention relates to automatic lighting systems and more specifically to automatic lighting systems for wheels and tires.
The invention disclosed here, distinguishes over the above referenced application with six novel features. First, the disclosed circuit uses a switch that is activated by deformation of the elastic tire material itself. This is not found in the above application and is not shown by any other reference. The use of the deformation-activated switch (or deformation-sensing switch) causes the lighting system to operate due to a completely different set of physical stimuli. Prior art uses sensors to detect motion through acceleration of the wheel. The lighting system disclosed here detects the tire""s interaction with the ground as it rolls, and is actually insensitive to acceleration in general. For proper operation, substantial contact is needed between the elastic tire and the deformation-sensing switch. In all prior art references this is immaterial for proper operation of the lighting system. Second, the use of a delay circuit to slow activation of the illumination system is no longer needed for this new design. This is because the photo-sensing circuit and the deformation-activated switch are placed in close proximity to one another so that the photocell is near the ground and clear of any shadows caused by the skate shoe or wheel housing when the switch activates the circuit to measure ambient light. Prior art either makes no attempt at addressing this problem or uses delay circuits and averaging circuits to try and determine the actual ambient light. The disclosed invention, because of this, is effective at measuring the actual ambient light level. Third, none of the cited references show an illuminated wheel where the activation of the circuit, and subsequent measuring of the ambient light conditions, only occurs over a small portion of the wheel""s rotation. This allows the designer to choose the position of the photocell when detection of light will occur, which in turn allows for optimum operation. Fourth, since the activation of the switch is intermittent, activating once each cycle for a short portion of the wheels rotation, the physical relationship between the switch and photocell is critical. All other prior art use acceleration activated motion sensors which turn on, and remain on, when a wheel is in use. Thus, prior art cannot provide timing for the positioning of the photo sensor so that it properly samples the ambient light conditions. With the disclosed invention the placement of the photocell near the activation switch is very important for proper operation, prior art does not even address such a need. Fifth, the photo sensor does not need a circuit to average the ambient light detected by the photo sensor as in application Ser. No. 09/346,918. It is not needed since the disclosed deformation switch allows sampling to take place only when the photocell is near the ground and unobstructed by the skate shoe and housing. Thus, the xe2x80x9cactualxe2x80x9d ambient light level can be sampled and xe2x80x9cstoredxe2x80x9d for the remainder of the wheel""s revolution. Sixth, the disclosed invention allows precisely timed intermittent illumination of the circuit. The use of a switch that activates upon the deformation of the tire as it contacts the ground allows the activation of the illumination device during a specific portion of the wheel rotation. With this control the illumination device can be made to turn xe2x80x9cONxe2x80x9d only during the portion of its rotation while it is clear of the skate wheel assembly (i.e. the wheel support channel on a roller blade skate), so that light output is used more efficiently. All prior art either activates continuously, or oscillates randomly with respect to the wheel""s rotation.
The use of lights on rotating assemblies, such as, bicycle and roller skate wheel is well known. Most systems for illuminating wheels and toys involve a battery, a manual switch, and an illumination device connected in series. The only problem with these designs is that they must be turned on by the user and also turned off. Since the most likely user of such devices are children, it is unlikely that such a system will be used properly. Either the light is not turned on at dusk or when they are turned-on, the light is not turned-off, thus draining the battery, making it unworkable to permanently seal the circuit within the elastic material.
To get around these problem a number of inventions have been designed which use the rotating motion of the wheel or toy to generate electricity to power the lights. In this way there are no external switches to turn on and off and no batteries to change. An examples of such a generator powered wheel is shown in U.S. Pat. No. 5,718,499 to Caro for a xe2x80x9cRoller Blade Wheel Lighting Systemxe2x80x9d. However, these systems are complicated, heavy, expensive to build, and are prone to failure under the harsh environment kids place them in. They also create a constant drag on the wheels which is undesirable. These systems also require specially designed skate shoes and attachments which adds to cost. The invention disclosed here does not suffer from these problems and can be used with standard roller skates wheels, standard motor vehicle tires, etc. And because the electronic circuit can be completely sealed inside a polymer or urethane tire, with no moving parts, and no external switches, its reliability is far superior to any of the generator powered designs.
Another way inventors have tried to eliminate the use of external switches is to include an acceleration sensor (i.e. motion sensor, acceleration switch, accelerometer, etc.). By including such a circuit, battery power is conserved because the device only lights when moved at sufficiently high accelerations. The use of acceleration sensors are shown in U.S. Pat. No. 5,683,164 to Chien for an xe2x80x9cIlluminated Wheelxe2x80x9d, U.S. Pat. No. 5,580,092 to Hsu et al. for a xe2x80x9cRoller Skate Wheel with Light Producing Meansxe2x80x9d, U.S. Pat. No. 5,536,074 to Hsu for a xe2x80x9cLight-Generating Wheel for an In-line Skatexe2x80x9d, U.S. Pat. No. 5,475,572 to Tseng for a xe2x80x9cLight Emitting Roller for Roller Skatesxe2x80x9d, U.S. Pat. No. 5,294,188 to Vancil for an xe2x80x9cIlluminated Roller Skate Wheelxe2x80x9d, and U.S. Pat. No. 4,363,502 to Rakerman for an xe2x80x9cIlluminative Skate Wheelxe2x80x9d. More advanced designs include circuit delays such as that shown in U.S. Pat. No. 5,653,523 to Roberts for a xe2x80x9cMiniature Centrifugal Lighting Assemblyxe2x80x9d. In this last design uses a delay circuit to keep the lights on for a short time after motion has stopped. This allow the lights to continue operating even if the user pauses for a moment to rest, but shuts off after a predetermined time period. These designs are all workable systems, but still waste a great deal of battery power during the daytime when the lights are not really needed.
U.S. patent No. 5,803,574 to Szaniszlo shows a safety light for bicycle wheels which uses an acceleration switch and photo sensor to control activation only when sufficiently dark out. The acceleration switch however is unstable and produces different outputs depending on the wheel""s speed of rotation. Because of this instability, a delay circuit is needed to latch the acceleration switch""s contact when it occurs. However, their is no specific point in the rotation that the acceleration switch is activated, thus, the activation point can not be controlled. The disclosed invention keep very precise control over when the circuit is activated and does not depend on the rotation speed of the wheel. Thus, timing can be precisely controlled to place the photocell far away from obstructions that might cause a false reading of ambient light levels (i.e. when a wheel is partially shrouded). This is something Szaniszlo""s design can not do. The disclose invention provides this control by using a deformation-activated sensor which reacts to totally different physical stimuli than an acceleration switch. An acceleration switch requires rotation or vibration of the wheel for activation, while the deformation switch activates from pressure placed on the tire portion of the wheel. Thus, the disclosed invention is immune to jarring and vibration that occurs during shipment. This eliminates the need for an enabling switch that Szaniszlo""s design requires, to prevent draining the battery during shipping and handling. Szaniszlo teaches only the installation of his device on bicycle wheels. While his device could be used other places it would require extensive modifications to be placed within a in-line roller blade wheel and a motor vehicle tire sidewall.
The disclosed invention does not suffer from the above limitations. An automatic deformation-activated switch limits power usage to only times when rolling on a surface, and a photo sensor allows power drain only during times of low ambient light. This combination saves battery power and results in battery use that is over four times less that Roberts centrifugal light design. Even more energy can be saved by not using a delay circuit which results in short bursts of light when the deformation-activated switch is activated each revolution of the tire. Because the battery is easily the most costly part of the entire circuit, the use of a smaller battery can save money and space in the design. In fact, the proposed safety light saves so much power, the circuit can be completely sealed inside a housing and the battery(ies) never need to be changed for the life of the wheel or tire. An in-line roller skate wheel lasts 50 to 200 hours depending on the surface which it is used. If we assume that less than 25 percent of the time it will be used in the dark, an operational battery life of approximately 30 to 50 hours should be sufficient to last the life of the wheel. For an in-line skate wheel this battery life can be achieved by the disclose invention with a single lithium button battery. Without the photo sensor circuit and automatic pressure switch, a roller blade or roller skate wheel would run out of power before the wheel was completely used, or would require a much larger battery(ies), or operate at much lower power which reduces visibility. This is a safety hazard for children since they will in general use the wheel until it is completely wore out. The addition of a photo sensor adds very little to the cost of the circuit, and more than pays for itself by reducing the size of the battery and allowing operation of the wheel during the day without draining the battery.
If a delay circuit is not used in the disclosed invention, the light output will be in short bursts as the deformation-activated switch is pressed. This further extends the life of the battery. Each illumination device may be activated for less than 25% of the wheel""s rotation. Since the activation position can be controlled, all the light output can be emitted so that it is seen, that is, no light is wasted illuminating the inside of a wheel channel or fender. Thus, the circuit can use four times less power or provide illumination that is 4 times brighter than even the Applicants prior art U.S. Pat. No. 6,175,196 xe2x80x9cPhoto-Sensitive Illuminated Skate Wheelxe2x80x9d.
This circuit if mounted in the side walls of car and motorcycle tire would provide good side visibility at night. The placement in motor vehicle tires (cars, motorcycle, 3-wheelers, etc.) could be especially important for motorcycles which are most likely not to be seen at night. By placing a deformation-activated switch in the side-wall of the tire, the circuit can be activated by the change in bending(deformation) of side-wall caused by compression of the tire against the pavement. A modem automotive tire lasts about 50,000 miles. If we assume an average speed of 50 miles per hour this means the tire will last approximately 1,000 hours. If one quarter of this driving occurs at night then only 250 hours of battery life is needed for the lighting system to last the life of the tire. Using a single lithium AA sized battery, such a safety light circuit will provide well over 250 hours of battery life and could even last 1000 hours depending on how the circuit is designed.
The invention disclosed here is especially designed for operation within in-line skate wheels, and motor vehicle tires (car, motorcycle, etc.), though it may also be used in roller skate wheels and other wheels which are constructed of elastic tire materials that are deformed during use. For these types of wheels, the periodic deformation of the wheels as they rotates against the ground can be detected by a properly placed pressure switch, so that the deformation of the elastic tire is detected. This deformation is used to activate a pressure switch which turns on the lighting system to provide a flashing or rotating pattern depending on the circuit""s design. The flashing or rotating pattern easily catches ones eye. The rotating pattern provides easily identified as a rolling vehicle even when no other part of the vehicle can be seen. If the circuit is place in a ball, the deformation of the ball material when bounced against a surface is detected by a pressure switch which activates due to this deformation.
Accordingly, several objects and advantages of this invention are:
a) To use of a deformation-activated switch to eliminates accidental activation due to vibration during transport. The deformation-activated switch is only activated when the wheel is in use and rolling on a surface with pressure.
b) To provide a safety light which allows brighter operation for a given battery size and operational life by reducing actual xe2x80x9cONxe2x80x9d time to only times when: 1) the deformation of the wheel""s tire is detected, and 2) low ambient light is detected.
c) To provide a safety light for a tire which can reliably be activated over a specific arc section in its rotation, while remaining xe2x80x9coffxe2x80x9d during the remainder of the wheel""s revolution.
d) To provide a safety light for a tire, which can: 1) be reliably activated over a specific arc section in its rotation while remaining xe2x80x9coffxe2x80x9d during the remainder of the wheel""s rotation, and 2) be activated only when the safety light detects a substantially dark environment.
e) To provide a safety light which allows brighter operation for a given battery size and operational life by reducing actual xe2x80x9cONxe2x80x9d time to only times when: 1) the deformation of the wheel""s tire is detected, 2) a photocell detects low ambient light levels, and 3) over a specific arc section of rotation so the illumination device is not hidden behind any obstructions while illuminated.
f) To provide ambient light sensing when the deformation-activated switch is activated, which allows the photo-sensor photocell to be at a known position in its rotation when activated. This allows the photo sensor to activate when it is not obstructed by a wheel support or shroud. Thus, the Safety Light circuit can easily detect the true ambient light level.
g) To provide a safety light for a tire, which can: 1) be activated only when the safety light detects a substantially dark environment and 2) activate and remain xe2x80x9conxe2x80x9d for a specified time after the deformation sensor detects deformation of the tire. Thus, the illumination of the system has a delay that keeps it xe2x80x9conxe2x80x9d for a short time after the deformation sensor no longer detects deformation of the tire.
h) To provide detection of rate of-change in deformation of an elastic tire for sending an xe2x80x9cONxe2x80x9d signal that a wheel or tire is rolling on a surface. This mode of detection is especially important for automotive tires where the vehicle""s weight is always present that can deform the tire. Thus, by detecting the rate-of-change in deformation, instead of a specific amount of deformation, an automotive tire can be park on the deformation-sensing switch side of the tire without causing the deformation switch to stay activated.
i) To provide a safety light for a tire, which can: 1) be activated only when the safety light detects a substantially dark environment and 2) be activate only while a significantly high rate-of-change in deformation of the tire is detected. Thus, the illumination of the system is active only in the dark and while the deformation sensor detects a significantly high rate-of-change in deformation of the tire.
j) To provide a safety light for a tire, which can: 1) be activated only when the safety light detects a substantially dark environment and 2) be activate and remain xe2x80x9conxe2x80x9d for a specified time by the deformation sensor detecting a significantly high rate-of-change in deformation of the tire. Thus, the illumination of the system has a delay that keeps it xe2x80x9conxe2x80x9d for a short time after the deformation sensor no longer detects the high rate-of-change in deformation of the tire.
k) To provide a safety light compact enough to fit within an in-line roller skate wheel, and illuminating the wheel only when used in the dark.
l) To provide a means for using a much smaller battery than would normally be possible, where substantial reductions in power consumption is achieved by limiting activation of the safety light to only times when the wheel is in use and also in a dark environment.
m) To provide a safety light for wheels that is highly reliable, and automatically activating when needed.
n) To provide a safety light compact enough to fit in within the side-wall of a motor vehicle wheel to provide side lighting when in use, and able to detect deformation of the tire sidewall.
o) To eliminate external switches and eliminate the need to change batteries, whereby the Safety Light can be completely sealed within its housing to provide a water-tight and airtight enclosure.
p) To provide a circuit that can withstand the injection molding process of molding the tire section around it. Insulation is used to help protect sensitive components from the heat.
q) To provide focused LED light from the sides of the wheel so that people viewing from the side of the wheel will see vary bright light output.
r) To provide an automatic battery-powered lighting systems for wheels where the battery lasts the life of the device.
s) To use Light Emitting Diodes (LEDs) to provide efficient light production to further extending battery life.
t) To provide the combination of high efficiency LEDs and Lithium battery which makes a very compact lighting system with an exceptionally long operational life.
u) To provide a delayed turn-off of safety light illumination when deformation of the tire is no longer detected, thus providing safety illumination even when the user momentarily stops.
v) To provide a saftey light circuit for tires that detects the state-change of a deformation-sensing switch. When the switch changes state (conductive to nonconductive, or nonconductive to conductive) due to deformation of an elastic tire, and is in a dark environment, the circuit is activated to provide illumination. This mode of detection is especially important for automotive tires where the vehicle""s weight is always present to deform the tire. Thus, by using the switching of the switch, instead of the state of the switch, an automotive tire can be park on the deformation-sensing switch side of the tire without causing the deformation switch to stay activated.
w) To provide a safety light for a tire, which can: 1) be activated only when the safety light detects a substantially dark environment and 2) be activate only for a predetermined amount of time after a deformation-sensing switch changes state. Thus, the illumination of the system is active only in the dark and for a time after the deformation sensing switch changes state.
x) To provide a safety light for a tire, which can: 1) be activated only when the safety light detects a substantially dark environment and 2) be activate by a deformation-sensing switch and 3) after being activated slowly shutoff independent of the final state of the switch.